The present invention relates to ventilators for installation in openings formed in the foundation of a dwelling or other building structure. In particular, the present invention relates to a shallow-profile foundation ventilator that is especially suited for applications requiring a replacement or retrofit ventilator.
Conventional shallow-profile ventilators are installed as original equipment during construction of a house or other building and are sometimes known as "primary" ventilators to indicate that they are part of the original building structure. Such primary ventilators typically have projections, sometimes referred to as "lintels," extending from the top of the ventilator. The projections rest on top of a course of brick and are sandwiched between another course of brick placed on top of the projections. Thus, conventional shallow-profile ventilators require mortar for their installation and are not suitable for most replacement or retrofit applications. Accordingly, conventional shallow-profile ventilators are best suited for primary use, and either require mortar for installation or have integral lintels, which make retrofit use impossible.
One type of a conventional retrofit foundation ventilator typically has a body including a front flange which rests against the outside-facing perimeter of the foundation opening. Such conventional retrofit ventilators also typically have a body, the depth of which extends a significant distance from the flange into the installation opening. U.S. Pat. No. 4,587,892 discloses an example of such type of a typical replacement or retrofit foundation ventilator which includes a peripheral flange 16 and an inner portion of the mounting frame broadly indicated at 30. Additional examples of such conventional retrofit foundation ventilators include those shown in U.S. Pat. Nos. 4,210,279 and 4,493,456.
The above-described conventional foundation ventilator configuration presents significant installation problems for certain kinds of foundation openings. A large number of dwellings and other building structures have been refurbished by the installation of wood shingling, aluminum siding or vinyl siding over the original outside finish of the structure. The installation of the siding often results in foundation openings which are partially covered by overhanging siding. This reduces the exterior size of the foundation opening and renders installation of conventional foundation ventilators such as those described above, difficult or impossible. This is because in many instances, the combination of the peripheral flange and the depth of the housing produces a shape which cannot be manuevered into the opening for installation. Cutting away the overhanging portion of the siding results in an aesthetically displeasing appearance of the siding where portions are cut away to permit installation of a conventional foundation ventilator.
In other cases, foundation openings are already fitted with a grille or ventilator structure that is recessed a short distance from the front of the foundation opening. Such grilles or ventilators lack the kind of peripheral flange of the conventional ventilators described above. However, removal of these so-called "recessed" grilles or ventilator structures often requires much effort and difficulty due to rusting or encrustation of mortar or cement around the structure.
Another type of ventilator has an intermediate depth profile which requires about twice the depth clearance in the foundation opening as a shallow depth profile ventilator, but less opening depth clearance than a conventional retrofit foundation ventilator such as described above. Examples of so-called intermediate depth ventilators include U.S. Pat. Nos. 4,231,514 and 4,249,460. One reason for the additional opening clearance required by such intermediate depth ventilators is the need to permit the opening mechanism to expand backward into the foundation opening. In U.S. Pat. No. 4,231,514 for example, movable louver panels 40, 42 (FIG. 3) move away from the ventilator body 10 and toward the back of the foundation opening as the ventilator opens to admit more air therethrough (column 4, lines 42-63). If such intermediate depth ventilators are to be used as replacement ventilators, removal of the original ventilator or grille is required. Moreover, such intermediate depth ventilators require mortar for their installation.